在安卓系统中使用Firebase与Likes Counter混淆

Question

我是初学者，正在开发一个android项目，用户喜欢管理员为他们发布的帖子。当用户点击点赞按钮时，点赞会更新为firebase。问题是，即使用户喜欢或不喜欢这篇帖子，点赞数也在增加。请调查一下。

注意：

Log.d(TAG, "Liked onDataChange: "+isLiked);

无论我们喜欢还是不喜欢shinebutton，都返回false。Shinebutton是一个库。

链接到其GitHub：Shinebutton Github

onLike方法：

@Override
public void onLike(View v, int position) {
UploadImage selectedItem = mUploads.get(position);
String selectedKey = selectedItem.getKey();
final ShineButton shineButton = new ShineButton(Objects.requireNonNull(getActivity()));
shineButton.setBtnFillColor(RED);
shineButton.setShapeResource(R.raw.heart);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(100,100);
shineButton.setLayoutParams(layoutParams);

final DatabaseReference likesRef = FirebaseDatabase.getInstance().getReference().child("ImageUploads").child(selectedKey).child("likes");
likesRef.addListenerForSingleValueEvent(new ValueEventListener(){
@Override
public void onDataChange(@NotNull DataSnapshot dataSnapshot) {
long numLikes = 0;
if(dataSnapshot.exists()){
numLikes = dataSnapshot.getValue(Long.class);
}
boolean isLiked = shineButton.isSelected();
Log.d(TAG, "Liked onDataChange: "+isLiked);
if(isLiked){
//If already liked then user wants to unlike the post
likesRef.setValue(numLikes-1);
}else {
//If not liked already then user wants to like the post
likesRef.setValue(numLikes+1);
shineButton.setEnabled(false);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
ShineButton like  =  layout.findViewById(R.id.like_feed);
System.out.println(RED);
like.setBackground(getResources().getDrawable(R.drawable.like_feed_bg));
}

代码修改后：现在，尽管我们喜欢或不喜欢，计数并没有增加或减少。

类似方法：

public void onLike(View v, int position) {
UploadImage selectedItem = mUploads.get(position);
String selectedKey = selectedItem.getKey();
final ShineButton shineButton = new ShineButton(Objects.requireNonNull(getActivity()));
shineButton.setBtnFillColor(RED);
shineButton.setShapeResource(R.raw.heart);
LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(100,100);
shineButton.setLayoutParams(layoutParams);
final DatabaseReference likesRef = FirebaseDatabase.getInstance().getReference().child("ImageUploads").child(selectedKey).child("likes");
likesRef.addListenerForSingleValueEvent(new ValueEventListener(){
@Override
public void onDataChange(@NotNull final DataSnapshot dataSnapshot) {
long numLikes = 0;
if(dataSnapshot.exists()){
numLikes = dataSnapshot.getValue(Long.class);
}
final long finalNumLikes = numLikes;
shineButton.setOnCheckStateChangeListener(new ShineButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(View view, boolean checked) {

if (checked){
likesRef.setValue(finalNumLikes-1);
}
else{
likesRef.setValue(finalNumLikes+1);
}
}
});
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
ShineButton like  =  layout.findViewById(R.id.like_feed);
System.out.println(RED);
like.setBackground(getResources().getDrawable(R.drawable.like_feed_bg));
}

Answer 1

问题是您没有检查被按下按钮的状态。您可以通过以下操作来实现这一点：

替换：

if(isLiked){ 
//If already liked then user wants to unlike the post 
likesRef.setValue(numLikes-1); }
else { 
//If not liked already then user wants to like the post 
likesRef.setValue(numLikes+1);
shineButton.setEnabled(false); 
}

有了这个：

shineButton.setOnCheckStateChangeListener(new ShineButton.OnCheckedChangeListener() { 
@Override 
public void onCheckedChanged(View view, boolean checked) { 
if (checked){
likesRef.setValue(numLikes+1);
} else {
likesRef.setValue(numLikes-1);
}
} 
});

当您关闭应用程序时，您还必须保留botton的引用。可以使用SharedPreferences执行此操作。